package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IUserService userService;
    /**
     * 关注
     * @param followUserId 被关注用户id
     * @param isFollow 关注还是取关
     * @return
     */
    @Override
    public Result follow(Long followUserId, Boolean isFollow) {
        //获取登录用户
        Long userId = UserHolder.getUser().getId();
        String key = "follows:" + userId;
        // 1.判断到底是关注还是取关
        if (isFollow) {
            // 2.关注，新增数据
            Follow follow = new Follow();
            follow.setFollowUserId(followUserId);
            follow.setUserId(userId);
            boolean isSuccess = save(follow);
            //当你关注一个用户后，我把关注的用户对象不仅写入数据库，也写入redis，方便后面取交集求共同关注用户
            if (isSuccess) {
                stringRedisTemplate.opsForSet().add(key,followUserId.toString());
            }
        }else {
            // 3.取关，删除 delete from tb_follow where user_id = ? and follow_user_id = ?
            boolean isSuccess = remove(new QueryWrapper<Follow>()
                    .eq("user_id", userId)
                    .eq("follow_user_id", followUserId));
            if (isSuccess) {
                //把关注用户的id从redis集合中移除
                stringRedisTemplate.opsForSet().remove(key,followUserId.toString());
            }
        }
        return Result.ok();
    }

    /**
     * 是否关注
     * @param followUserId
     * @return
     */
    @Override
    public Result isFollow(Long followUserId) {
        //select * from table where user_id = ? and follow_user_id = ?
        Integer count = query()
                .eq("follow_user_id", followUserId)
                .eq("user_id", UserHolder.getUser().getId())
                .count();
        return Result.ok(count > 0);
    }

    /**
     * 共同关注
     * @param id
     * @return
     */
    @Override
    public Result followCommons(Long id) {
        //获取当前用户
        Long userId = UserHolder.getUser().getId();
        //求交集
        String key = "follows:" + userId;
        String key2 = "follows:" + id;
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect(key, key2);
        //这里是id集合，转成Long类型
        if (intersect.isEmpty() || intersect ==null) {
            return Result.ok(Collections.emptyList());
        }
        List<Long> list = intersect.stream().map(Long::valueOf).collect(Collectors.toList());
        //user转成userDTO类型
        List<UserDTO> users = userService.listByIds(list).stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());

        return Result.ok(users);
    }
}
